Identify the type of system if boiling water is kept in a half-filled closed vessel.

One mole of an ideal gas at $25\,^{\circ}C$ expands its volume from $1\,L$ to $4\,L$ at constant temperature. What work (in $J$) is done if the gas expands against a vacuum $(P_{ext} = 0)$?

What is an exothermic reaction and an endothermic reaction?

Among the following,the number of state variables is $.....$
Internal energy $(U)$; Volume $(V)$; Heat $(q)$; Enthalpy $(H)$

If $\Delta H$ is the change in enthalpy,$\Delta U$ is the change in internal energy,$N_P$ is the number of moles of products,and $N_r$ is the number of moles of reactants,then which of the following is correct for a gaseous reaction?

An ideal gas is allowed to expand from $1 \, L$ to $10 \, L$ against a constant external pressure of $1 \, bar$. The work done in $kJ$ is